The present invention relates to polymers of propene consisting of from 50 to 99.9% by weight of an isotactic propene copolymer (A') and from 0.1 to 50% by weight of a propene homopolymer or a propene copolymer (B'), wherein
a) the propene copolymer (A') consists of from 80 to 99.9 mol % of propene and from 0.1 to 20 mol % of ethene and/or a C.sub.4 -C.sub.12 -1-olefin, at least 80% of all propene diads are isotactic meso diads, the propene copolymer (A') has a proportion (X.sub.S) of material soluble in xylene at 20.degree. C. which satisfies the inequality (1) EQU (X.sub.S)&lt;542 400 exp (-0.1T.sub.M)+0.5 (1), PA1 the tensile modulus of elasticity (E) of the propene copolymer (A') in MPa, determined in accordance with ISO 527, obeys the inequality (2) EQU (E)&gt;1.9.times.10.sup.-11 (T.sub.M).sup.6.34 +180MPa (2), PA1 where in both inequalities (1) and (2) T.sub.M is the melting point in .degree. C., and PA1 b) the propene homopolymer or the propene copolymer (B') consists of from 80 to 100 mol % of propene and from 0 to 20 mol % of ethene and/or a C.sub.4 -C.sub.12 -1-olefin, at least 55% of all regioregular propene diads are isotactic meso diads, an enthalpy of fusion .DELTA.H.sub.m of less than 50 J/g is observed in the DSC measurement of (B') and no crystalline ex sequences are detectable. PA1 B) at least one metallocene complex and PA1 C) a compound capable of forming metallocenium ions. PA1 A) an organic or inorganic support. PA1 M is titanium, zirconium, hafnium, vanadium, niobium or tantalum or an element of transition group III of the Periodic Table and the lanthanides, PA1 X is fluorine, chlorine, bromine, iodine, hydrogen, C.sub.1 -C.sub.10 -alkyl, C.sub.6 -C.sub.15 -aryl, alkylaryl having from 1 to 10 carbon atoms in the alkyl radical and from 6 to 20 carbon atoms in the aryl radical, --OR.sup.10 or --NR.sup.10 R.sup.11, PA1 n is an integer from 1 to 3, where n corresponds to the valence of M minus 2, PA1 R.sup.10 and R.sup.11 are C.sub.1-C.sub.10 -alkyl, C.sub.6 -C.sub.15 -aryl, alkylaryl, arylalkyl, fluoroalkyl or fluoroaryl each having from 1 to 10 carbon atoms in the alkyl radical and from 6 to 20 carbon atoms in the aryl radical, PA1 R.sup.5 to R.sup.9 are hydrogen, C.sub.1-C.sub.10 -alkyl, 5- to 7-membered cycloalkyl which in turn may bear a C.sub.1-C.sub.10 -alkyl group as substituent, C.sub.6 -C.sub.15 -aryl or arylalkyl, where two adjacent radicals may also together form a saturated or unsaturated cyclic group having from 4 to 15 carbon atoms, or Si(R.sup.12).sub.3 where PA1 R.sup.12 is C.sub.1-C.sub.10 -alkyl, C.sub.3 -C.sub.10 -cycloalkyl or C.sub.6 -C.sub.15 -aryl, ##STR2## PA1 where the radicals PA1 R.sup.13 to R.sup.17 are hydrogen, C.sub.1-C.sub.10 -alkyl, 5- to 7-membered cycloalkyl which may in turn bear a C.sub.1-C.sub.10 -alkyl group as substituent, C.sub.6 -C.sub.15 -aryl or arylalkyl, where two adjacent radicals may also together form a saturated or unsaturated cyclic group having from 4 to 25 carbon atoms, or Si(R.sup.18).sub.3 where PA1 R.sup.18 is C.sub.1-C.sub.10 -alkyl, C.sub.6 -C.sub.15 -aryl or C.sub.3 -C.sub.10 -cycloalkyl, PA1 where PA1 R.sup.20, R.sup.21 and R.sup.22 are identical or different and are each a hydrogen atom, a halogen atom, a C.sub.1 -C.sub.10 -alkyl group, a C.sub.1 -C.sub.10 -fluoroalkyl group, a C.sub.6 -C.sub.10 -fluoroaryl group, a C.sub.6 -C.sub.10 -aryl group, a C.sub.1 -C.sub.10 -alkoxy group, a C.sub.2 -C.sub.10 -alkenyl group, a C.sub.7 -C.sub.40 -arylalkyl group, a C.sub.8 -C.sub.40 -arylalkenyl group or a C.sub.7 -C.sub.40 -alkylaryl group or two adjacent radicals together with the atoms connecting them form a ring, and PA1 M.sup.2 is silicon, germanium or tin, ##STR4## PA1 where PA1 R.sup.23 is C.sub.1 -C.sub.10 -alkyl, C.sub.6 -C.sub.15 -aryl, C.sub.3 -C.sub.10 -cycloalkyl, alkylaryl or Si(R.sup.24).sub.3, PA1 R.sup.24 is hydrogen, C.sub.1 -C.sub.10 -alkyl, C.sub.6 -C.sub.15 -aryl which may in turn bear C.sub.1 -C.sub.4 -alkyl groups as substituents or C.sub.3 -C.sub.10 -cycloalkyl PA1 R.sup.5 and R.sup.13 are identical and are hydrogen or C.sub.1 -C.sub.10 -alkyl, PA1 R.sup.9 and R.sup.17 are identical and are hydrogen, methyl, ethyl, isopropyl or tert-butyl, PA1 R.sup.6, R.sup.7, R.sup.14 and R.sup.15 have the meanings R.sup.7 and R.sup.15 are C.sub.1 -C.sub.4 -alkyl R.sup.6 and R.sup.14 are hydrogen or two adjacent radicals R.sup.6 and R.sup.7 or R.sup.14 and R.sup.15 together form a cyclic group having from 4 to 25 carbon atoms, ##STR6## PA1 M is titanium, zirconium or hafnium and PA1 X is chlorine, C.sub.1 -C.sub.4 -alkyl or phenyl. PA1 M is titanium or zirconium, PA1 X is chlorine, C.sub.1 -C.sub.4 -alkyl or phenyl, ##STR7## PA1 and PA1 R.sup.5 to R.sup.7 and R.sup.9 are hydrogen, C.sub.1 -C.sub.10 -alkyl, C.sub.3 -C.sub.10 -cycloalkyl, C.sub.6 -C.sub.15 -aryl or Si(R.sup.12).sub.3, or two adjacent radicals form a cyclic group having from 4 to 12 carbon atoms. PA1 M.sup.3 is an element of main group III of the Periodic Table, in particular B, Al or Ga, preferably B, PA1 X.sup.1,X.sup.2 and X.sup.3 are hydrogen, C.sub.1-C.sub.10 -alkyl, C.sub.6 -C.sub.15 -aryl, alkylaryl, arylalkyl, haloalkyl or haloaryl each having from 1 to 10 carbon atoms in the alkyl radical and from 6 to 20 carbon atoms in the aryl radical or fluorine, chlorine, bromine or iodine, in particular haloaryls, preferably pentafluorophenyl.
The present invention further relates to a process for preparing polymers of propene, their use for producing films, fibers and moldings and also the films, fibers and moldings obtainable in this way.
Random propene copolymers with ethene or with a higher 1-olefin as comonomer prepared using metallocene catalyst systems are well suited to numerous applications in plastics technology (EP-A 668 157, DE-A 19 533 337). This is also true of multiphase propene copolymers, as described in EP-A 643 084, which can also consist of a plurality of different propene copolymers and are used, for example, for producing films, fibers or moldings.
Such random propene copolymers are used, inter alia, in injection molding, particularly in thin-wall injection molding, for example in the production of transparent packaging containers. Here, importance is attached both to high stiffness and transparency of the material and also to a minimum degree of impact toughness and thus resistance to breakage of the moldings produced. In the packaging sector, particularly when foods are to be packed, or in medical applications such as disposable syringes, low proportions of extractable material are often also required.
Compared to propene copolymers prepared using Ziegler-Natta catalysts, random propene copolymers prepared using metallocene catalysts have, at comparable melting points, higher stiffness, better transparency and very low proportions of extractable material [M. -J. Brekner: "Metallocene Based Isotactic Polypropylene For Selected Applications", Proc. Metallocens '96, p. 155 ff., Dusseldorf, Mar. 6-7, 1996; J. J. McAlpin: "Enhanced Performance for Exxpol.TM. Propylene Polymers in Target Applications", Proc. SPO '95, p. 125 ff., Houston, Sep. 20-22, 1995]. However, they have a significantly lower impact toughness which breaks down virtually completely at temperatures as high as 0.degree. C. For this reason, it is precisely in this area of transparent food packaging where a high resistance to breakage is required even at refrigerator temperatures that random propene copolymers produced using metallocene catalysts are inferior to their conventional predecessors.